1. Field of the Invention
The present invention relates to systems for printing on sheets of materials, such as fabric, and particularly to a system which can employ a plurality of different sized backing rollers at different positions around a common center drive roller and can utilize different printing devices at different locations.
2. Description of the Prior Art
Presently known printing systems utilize center gears a rollers to drive a plurality of printing rollers and intermediate or idler rollers. Endless belts or sleeves are formed around the intermediate and drive rollers and sheets of material are fed over the sleeve and rollers past outer printing rollers which apply liquids to the sheets for printing thereon. The intermediate rollers and printing rollers are generally at fixed locations and each set of rollers are of equal size diameters. Examples of such prior art systems are found in U.S. Pat. Nos. 2,213,569, 1,855,525, and 1,011,508, each of which utilize a plurality of identical printing or spaced intermediate rollers. While the latter patent mentions the use of cylinders of different diameters, these are all of the same size at one time and not different sizes used together. U.S. Pat. No. 2,633,755 shows a device for adjusting the position of drive wheels for printing rollers, but these are all of equal sizes and adjusted as a group rather than independently. Another adjustable printing apparatus is shown in U.S. Pat. No. 3,026,798 which permits angular adjustment of intermediate gears about a central cylinder, but the gears are likewise of the same size at all locations.
Various printing devices are also available for applying liquids to sheets of material or substrates which are fed over the contacting surfaces of the devices. These include rollers, as in the above mentioned patents, which rotate with a central driver roller and the moving sheet and stationary applicators which apply the liquids to the sheets as they pass against the surfaces of the applicators. Examples of the latter stationary devices are found in U.S. Pat. Nos. 3,014,454, and 4,133,293 of the present applicant. Generally only one type of printing device can be utlized in a particular printing system.